DE102017125569A1 - FLOW BOLT SCREW WITH REMOVED SPRING RING - Google Patents

Abstract

A screw for connecting workpieces, for example, automotive body panels, is provided which has a head portion, an externally threaded shaft extending from the head portion, a flow-hole forming tip disposed at a distal end portion of the male screw shaft, and a stepped one below the head portion Includes spring ring. The stepped spring ring is designed to apply a clamping load to the connected workpieces as they expand and contract.

Description

TERRITORY

The present disclosure relates generally to fasteners, and more particularly to fasteners for use in adjacent unilateral access components.

STATE OF THE ART

The statements in this area merely provide background information related to the present disclosure and do not necessarily represent the prior art.

Various connection designs often require one-way connection techniques to create efficient assemblies. One such technique of unilateral bonding is flow-drill screwing (FDS), which screws a fastening screw into a joint and produces the locknut in place during the screwing operation. When inserting a flow screw in thick materials or non-related materials, a through hole can be used. In addition, in the case of material stacks with thick wall thickness or when a top layer of sheet metal is thicker than a prescribed size (eg> 2 mm), a through-hole can be used in the top layer of the material.

Often an adhesive is used in conjunction with a Flließbohrschraube. There is a concern about torque drop when using an adhesive in a joint. Concerns about torque loss also exist with the use of polymer-based substrate materials. Torque loss occurs when the torque may decrease after the joint has been tightened to a certain torque. After the bonded parts go through painting processes and the adhesive cures, there may be some concern that the torque in the joint has changed.

This problem of torque drop in connected assemblies, among other mechanical connection problems, is addressed by the present disclosure.

PRESENTATION OF THE INVENTION

In one embodiment of the present disclosure, a screw is provided that includes a head portion, an externally threaded shaft extending from the head portion, a flow-hole forming tip disposed at a distal end portion of the male screw shaft, and a stepped spring ring disposed below the head portion. In one embodiment, the stepped spring ring defines a spring rate sufficient to prevent torque drop.

According to various embodiments of this screw, the recessed spring ring is integrally formed with the head portion and the head portion may define a tool engagement feature such as a hexagon. The stepped spring ring may also consist of a different material than the head portion, male thread shaft and the flow hole forming tip. In another embodiment, the recessed spring ring defines a flange that extends at least 90 ° from a longitudinal axis and a proximal end portion of the screw and may also define a flat, distal surface. In yet another embodiment, the screw defines regions of different hardness.

In another embodiment, a screw is provided having a head portion, an externally threaded shaft extending from the head portion, a flow-hole forming tip disposed at a distal end portion of the external thread shaft, and a stepped spring ring disposed below the head portion, the concave ring having a Defined flange which extends at least 90 ° from a longitudinal axis and a proximal end portion of the screw, wherein the stepped spring ring defines a spring rate, which is sufficient to prevent a torque drop.

In yet another embodiment, an assembly is provided that includes a plurality of workpieces and a screw disposed between the workpieces. The screw includes a head portion, an externally threaded shaft extending from the head portion, a flow hole forming tip disposed at a distal end portion of the male screw shaft, and a stepped spring ring disposed below the head portion. The workpieces may consist, inter alia, of a material selected from the group consisting of aluminum, polymers and polymer composites.

Other areas of application will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

list of figures

• 1 eine perspektivische Ansicht einer in Übereinstimmung mit den Prinzipien der vorliegenden Offenbarung konstruierten Schraube ist;
• 2 eine Querschnittsansicht der Schraube aus 1 ist;
• 3A eine Querschnittsansicht einer durch eine Schraube aus 1 verbundenen Baugruppe ist;
• 3B eine Querschnittsansicht einer durch eine Schraube aus 1 verbundenen Baugruppe ist und einen elastisch verformten abgesetzten Federring in Übereinstimmung mit den Lehren der vorliegenden Offenbarung aufweist;
• 4 eine Detailansicht von Detail A der 3B ist, eines Flansches der Schraube verbunden mit einem Werkstück in Übereinstimmung mit den Lehren der vorliegenden Offenbarung; und
• 5 eine Querschnittsansicht alternativer Ausführungsformen der in Übereinstimmung mit den Lehren der vorliegenden Offenbarung konstruierten Schraube ist.

In order that the disclosure may be well understood, various embodiments thereof will now be described by way of example, with reference to the accompanying drawings, in which:

• 1 Figure 3 is a perspective view of a screw constructed in accordance with the principles of the present disclosure;
• 2 a cross-sectional view of the screw 1 is;
• 3A a cross-sectional view of a through a screw 1 connected assembly is;
• 3B a cross-sectional view of a through a screw 1 connected assembly and having an elastically deformed remote spring ring in accordance with the teachings of the present disclosure;
• 4 a detail view of detail A of the 3B is a flange of the screw connected to a workpiece in accordance with the teachings of the present disclosure; and
• 5 Figure 4 is a cross-sectional view of alternative embodiments of the screw constructed in accordance with the teachings of the present disclosure.

The drawings described herein are for illustration only and are not intended to limit the scope of the present invention in any way.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or use. It should be understood that throughout the drawings, corresponding reference numbers indicate similar or corresponding parts or features.

Referring to the 1 and 2 For example, a screw is illustrated in accordance with the principles of the present disclosure and is generally indicated by the reference numeral 20 characterized. The screw 20 includes a head section 22 , an external thread shaft 24 that is different from the head section 22 extends, a flow-hole forming tip 26 arranged at a distal end portion 28 of external thread shaft 24 , and one under the head section 22 arranged remote spring ring 30 , The stepped spring washer 30 includes a side wall 32 extending from the head section 22 down to a flange 34 which extends from a longitudinal axis L of the screw 20 extends away. There is also a groove 36 generally under the head section 22 arranged as shown.

The stepped spring washer 30 is generally similar to a diaphragm spring, as the sidewall 32 and the flange 34 are designed to act on the head section when torque is applied 22 elastically deform and therefore act as a spring to apply and maintain a load on workpieces, as described in more detail below. Preferably, the stepped spring ring defines 30 a spring rate sufficient to prevent torque drop after the workpieces are joined and during thermal expansion and contraction of the joint.

The stepped spring washer 30 can, as shown, integral with the head portion 22 be formed, or the stepped spring ring 30 may alternatively be a separate part or a separate component. The stepped spring washer 30 can also be made of a different material than the head section 22 , the male thread shaft 24 and / or the flow-hole forming tip 26 consist.

The head section 22 defines a tool intervention feature 40 , which in this embodiment is a hexagonal geometry. Other tool-engaging features, such as slotted, hexagonal or hexalobular (Torx), can also be used. The tool intervention feature 40 may be on the outside, as shown, or the tool engaging feature 40 can in from the head section 22 while remaining within the scope of the present disclosure.

Referring now to the 3A and 3B is the screw 20 in workpieces 10 and 15 used, with integrally formed threads 17 in the workpieces 10 / 15 due to the flow drilling method, to a joint 19 to build,. When the connection point 19 expands and contracts, the offset spring ring bends 30 or deforms elastically and continues to exert a clamping load on the joint 19 out. 3A shows the screw 20 , which continues to exert a clamping load when the joint 19 expands and 3B shows the screw 20 , which continues to exert a clamping load when the joint 19 contracted.

Referring now to 4 is a detail of the flange 34 who is on the workpiece 10 is present, shown in more detail. The flange 34 in this embodiment extends at least 90 ° from the longitudinal axis L and a proximal end portion of the screw 20 , The term "distal" or "removed" as used herein is to be construed as in the direction of arrow X and the term "proximal" or "proximal" is to be interpreted as in the direction of arrow Y.

Alternatively, the flange can 34 extend by more than 90 °, as shown by the dashed lines, and consequently the flange 34 ' in good sealing contact with a surface 12 of the workpiece 10 stay. In these embodiments, the flange defines 34 / 34 ' a flat, distal surface 33 / 33 ' to provide an improved seal between the flange 34 / 34 ' and the workpiece 10 maintain. An improved sealing connection is important when the workpieces 10 / 15 go through various cleaning / dipping processes before painting, so that no dirt gets into the joint 19 and creates a cause for corrosion or other forms of deficiency.

The screw 20 can be made of any of a variety of materials and in one embodiment is made of high strength steel such as boron. In another embodiment, the screw is made of an aluminum material such as 7000 series aluminum. Other materials with the remote spring ring 30 and can withstand various processing conditions may also be used while remaining within the scope of the present disclosure.

The workpieces 10 / 15 can be made of any of a variety of materials, including, for example, aluminum, polymers, and polymer matrix composites. The reinforcements in the composites may be carbon fiber, glass fiber or other materials and may occur in a continuous or punctiform form. It is understood that these materials are merely exemplary and any material for the workpieces 10 / 15 may be used while remaining within the scope of the present disclosure.

Referring now to 5 Additional embodiments of a screw according to the teachings of the present disclosure are illustrated and generally indicated by the reference numeral 50 characterized. The screw 50 includes a stepped spring washer 52 with a slightly different sidewall geometry 54 namely, a curved / arcuate shape as shown. It is understood that this alternative geometry is intended to illustrate that any of a number of forms for the remote spring ring 30 / 52 can be used, provided the spring washer 30 / 52 is suitable to exert a clamping load when the joint 19 expands and contracts and preferably prevents a torque drop.

As in further 5 shown, the hardness of the screw 50 in different areas 1 . 2 and 3 be adapted, the area 1 a higher hardness in the area of the flow-hole forming tip 56 would better withstand the flow drilling process. Area 2 can have a lower hardness and range 3 even lower hardness to the required spring properties for the remote spring ring 52 provide.

Accordingly, the present disclosure provides an innovative fastener for joining workpieces with unilateral access and to inhibit torque drop. The invention is particularly useful for bonding composites to metal, and more particularly to carbon fiber composites with aluminum. Flow-tapping screws utilizing the unique features of the fasteners shown and described herein enable a high volume, one-sided connection, especially for joints comprising composites and metals.

The description of the disclosure is merely exemplary in nature, and thus variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.

Claims (15)

Screw comprising: a head portion; a male threaded shaft extending from the head portion; a flow-hole forming tip disposed at a distal end portion of the male thread shaft; and a arranged below the head portion remote spring washer. Screw after Claim 1 wherein the stepped spring ring is formed integrally with the head portion. A screw as claimed in any one of the preceding claims, wherein the head portion defines a tool engaging feature. Screw after Claim 3 where the tool engaging feature lies inboard of the head section. Screw after Claim 3 where the tool engaging feature lies outside of the head portion. Screw according to one of the preceding claims, wherein the stepped spring ring a spring rate defined, which is sufficient to prevent a torque drop. A screw according to any one of the preceding claims, wherein the recessed spring ring is made of a different material than the head portion, male thread shaft and the flow-hole forming tip. Screw after Claim 1 to 7 wherein the recessed spring ring defines a curved sidewall extending from the head portion to a flange. A screw according to any one of the preceding claims, wherein the recessed spring ring defines a flange extending at least 90 ° from a longitudinal axis and a proximal end portion of the screw. Screw after Claim 9 wherein the flange defines a planar, distal surface. A screw according to any one of the preceding claims, wherein the screw is made of a material selected from the group consisting of boron steel and 7000 series aluminum. A screw as claimed in any one of the preceding claims, wherein the screw defines regions of different hardness. Assembly comprising: a variety of workpieces; and the screw according to one of the preceding claims arranged between the workpieces. Assembly after Claim 13 wherein the workpieces are made of a material selected from the group consisting of aluminum, polymers and polymer matrix composites. Motor vehicle comprising the spring or assembly according to one of the preceding claims.

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